Understanding SWG

[Jenna74]

Hi,
Question, I installed a new SWG last month. The salt seems to be stable at 3000. The chlorine is very low, .5ish. Shouldn’t the SWG produce enough chlorine if the salt is at the right amount?
My PH is high and alkalinity at 170…maybe this is screwing up my chlorine?

Thank you,
Jennifer
Salt water, plaster pool, 20k gal, hot desert sun

 

[ajw22]

What model SWG do you have?

What is the SWG % set at and what is your pump runtime?

Please put specific model numbers in your signature.

 

[Jimrahbe]

Jen,

The cell will only make the amount of chlorine you tell it to make.

You have to run the cell long enough and hard enough for it to work.

We need to know what specific cell you have.

We need to know how long your cell/pump run each day.

We need to know the % of output you have to cell set to make.

We need to know the CYA (Stabilizer) level in your pool water.

Also, keep in mind that if you already have algae, the cell will never be able to make more chlorine than your pool can consume in a day.

Thanks,

Jim R.

 

[Jenna74]

It is set at 70%. Aftermarket cell compatible with Pentair Intellichlor IC40. Pump runs for 7 hours.

 

[Jenna74]

Jen,

The cell will only make the amount of chlorine you tell it to make.

You have to run the cell long enough and hard enough for it to work.

We need to know what specific cell you have.

We need to know how long your cell/pump run each day.

We need to know the % of output you have to cell set to make.

We need to know the CYA (Stabilizer) level in your pool water.

Also, keep in mind that if you already have algae, the cell will never be able to make more chlorine than your pool can consume in a day.

Thanks,

Jim R.

CYA is at 75

 

[Jenna74]

I will add chlorine and bump it up from 70% and test again, thank you

 

[ajw22]

It is set at 70%. Aftermarket cell compatible with Pentair Intellichlor IC40. Pump runs for 7 hours.

That would give you 1.7 ppm of FC.

Average daily need of FC is 3 ppm or more.

Even at 100% for 7 hours you will only get 2.4 ppm of FC. You need to increase pump runtime.

Running it at 70% for 13 hours will give you 3.2 ppm of chlorine.

 

[ajw22]

CYA is at 75

Your CYA is 80. We round up. If the dot disappears between 80 and 70 we round up and call it 80.

You can’t eyeball values since the scale is logarithmic, not linear. Halfway is not 5.

 

[Jimrahbe]

Jen,

Your cell should add 8 ppm of FC to your pool when running at 100% for 24 hours. Assuming everything is perfect.

That is .33 ppm per hour at 100% and .23 per hour at 70%. So, 7 hours will add about 1.6 ppm of FC to a pool that is using 2 to 4 ppm of FC per day.

At 70% you need to run for at least 13 hours to make just 3 ppm of FC (chlorine). It is best to overshoot and then reduce the cell's output rather than start low and try to catch up.

With a CYA of 80 your FC "Target" is 6 ppm. See the saltwater section of this chart. FC/CYA Levels

I suggest that you add enough liquid chlorine to get you up to 6 ppm and then let your SWCG keep in there.

Thanks,

Jim R.